AWS Certified Solutions Architect – Professional SAP-C01 – Question216

In Amazon RDS for PostgreSQL, you can provision up to 3TB storage and 30,000 IOPS per database instance. For a workload with 50% writes and 50% reads running on a cr1.8xlarge instance, you can realize over 25,000 IOPS for PostgreSQL. However, by provisioning more than this limit, you may be able to achieve:

A. higher latency and lower throughput.
B. lower latency and higher throughput.
C. higher throughput only.
D. higher latency only.

Correct Answer: B

Explanation:

Explanation: You can provision up to 3TB storage and 30,000 IOPS per database instance. For a workload with 50% writes and 50% reads running on a cr1.8xlarge instance, you can realize over 25,000 IOPS for PostgreSQL. However, by provisioning more than this limit, you may be able to achieve lower latency and higher throughput. Your actual realized IOPS may vary from the amount you provisioned based on your database workload, instance type, and database engine choice.
Reference:
https://aws.amazon.com/rds/postgresql/